This application relates to devices, techniques and materials related to biofuels.
Engineered fuel such as pure hydrogen and methane gases are difficult and costly to store and transport. For example, compressors needed to pressurize hydrogen and/or methane and other products can involve sizeable capital expenditures, large expenditures for electricity and attendant production of greenhouse gases, and high operating costs. Further, the pipelines for transporting the pressurized hydrogen and/or methane often incur costly maintenance and repair costs.
In addition to the compressed-gas fuel form, hydrogen can be converted to cryogenic liquid or slush for storage. Liquid hydrogen is generally stored at −420° F. (−252° C.) at atmospheric pressure and often transported through unprotected delivery lines, parts of which can be damaged due to atmospheric water vapor condensation and freezing. Storage and transport of cryogenic methane face similar costs.
Moreover, the high cost of storage and transport for hydrogen and methane is met with low energy density. For example, a gallon of cryogenic liquid methane at −256° C. provides an energy density of 89,000 BTU/gal about 28% less than a gallon of gasoline. Liquid hydrogen at −252° C. provides only about 29,700 BTU/gal or 76% less than gasoline.